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Sediment bacteria in an urban stream: Spatiotemporal patterns in community composition
Alescia A Roberto1, Jonathon B Van Gray1, Laura G Leff1
1Department of Biological Sciences, Kent State University, Kent, OH 44242, USA.
Water Research
|February 19, 2018
Summary
Urban discharge significantly alters stream sediment bacteria composition and distribution over space and time. Environmental factors, not functional profiles, drive these changes, highlighting niche filtering in lotic ecosystems.
Area of Science:
- Environmental Microbiology
- Ecosystem Ecology
- Biogeochemical Cycling
Background:
- Sediment bacteria are crucial for nutrient cycling in rivers.
- Urban discharge impacts on stream bacteria distribution are not well understood.
- Understanding these impacts is vital for managing aquatic ecosystems.
Purpose of the Study:
- To investigate how urban discharge affects the spatial and temporal distribution of stream sediment bacteria.
- To identify key environmental factors influencing bacterial community structure in response to urban discharge.
- To assess the impact of urbanization on bacterial diversity and composition in lotic systems.
Main Methods:
- Collected water and sediment samples from impacted and reference streams after large storm events.
- Analyzed bacterial community composition using 16S rDNA profiling.
- Utilized multivariate analysis to correlate community structure with abiotic parameters.
- Assessed bacterial community functional profiles.
Main Results:
- Alpha diversity remained spatially constant, but beta diversity and community composition showed significant spatial and temporal variation.
- Bacterial communities clustered based on location (upstream/reference vs. downstream Tinkers Creek).
- Specific bacterial families associated with pollution (Comamonadaceae, Rhodobacteraceae, Pirellulaceae, Sphingomonadaceae, Phyllobacteriaceae) were more abundant at impacted sites.
- Seasonal changes in community composition were observed, but functional profiles were unaffected by spatiotemporal variations.
Conclusions:
- Urban discharge and associated environmental drivers strongly shape sediment bacterial community structure through niche filtering.
- Local environmental conditions, particularly following discharge events, are key determinants of bacterial composition.
- While urbanization drives structure, dispersal limitations and species interactions may also influence community dynamics.
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